Histochemical characteristics of the anal sacs of the cat

The histochemistry of polysaccharides and proteins and the distribution of RNA were investigated in the glands and mature secretion of the anal sacs of the cat. Glycogen was extremely abundant in the epithelial lining of the lumen and efferent duct of the anal sac and also in ducts of sebaceous glands of the sacs constantly formed in the place of degenerating acini. Little glycogen was found in the unchanged sebaceous acini. The apocrine glands of the anal sacs were substantially richer in glycogen than the apocrine sweat glands of the skin and were in an active state. A high concentration of acid mucopolysaccharides was present in the mature secretion, and their source was the apocrine glands. The phases of the secretory cycle alternated in different cells and secretory portions of the apocrine glands highly asynchronously. Carboxylated acid mucopolysaccharides were more abundant than sulfated. Sialomucin, hyaluronic acid, and chondroitin sulfate could be identified in the secretion. Neutral and acid mucopolysaccharides were present in the mature secretion in the form of complexes with one another in approximately equal proportions; neutral polysaccharides consisted chiefly of glycogen. Besides polysaccharides, the apocrine glands produce large quantities of protein, in which the mature secretion was rich. This protein was predominantly basic, and the secretion contained very little acid protein. Maturing cells of the sebaceous acini, and also other specific sebaceous glands, were characterized by a much higher protein concentration than in ordinary sebaceous glands.